A pump system according to the present invention finds significant utility as a fluid pressure source for directing fluid under pressure through a "jetting" line; e.g., a hose or equivalent flexible conduit operative to clear blockages in fluid-conducting lines of the types commonly found in industrial environments; e.g., sewage lines, water lines, grease lines and the like. A typical jetter line has an outlet nozzle designed to pressurize the blockage while using part of the fluid pressure to advance the jetting line as the blockage deteriorates. Because lines requiring blockage removal are often sinous in parts, it is found that variations in fluid output or pulses from the pump pressurizing the jetting line is extremely helpful in causing the jetting line to accommodate all but the sharpest bends and curves. Accordingly, it is a principal object of the invention to provide a convertible pump system; that is, a pump system whose output is adjustably convertible between maximum output and a lesser output, and to achieve the conversion by simple and expedient means so that the pump is under control of the user at all times. A feature is the adaptability of the conversion system to existing pumps, thus effecting cost savings in manufacture, use and maintenance.
Further features, objects and advantages will appear as a preferred embodiment of the invention is developed in the ensuing description and accompanying drawings.